Second Jaw in Moray Eels

Hi All-Here is an abstract from the latest issue of Nature I thought would be very interesting to those with a science bent. It describes the function of the second set of "throat" jaws in Moray eels. I can not post the whole article without violating copyright. Email the author for a full reprint. I will try to get permission to post photos. There is a link to the video at the bottom which is public. I have read the article and the figures are extremely cool and very informative. I had no idea about this anatomy in eels. It must have been the inspiration for the movie Aliens.

Nature 449, 79-82 (6 September 2007).

Raptorial jaws in the throat help moray eels swallow large prey

Rita S. Mehta1 & Peter C. Wainwright1

1. Section of Evolution and Ecology, University of California, One Shields Avenue, Davis, California 95616, USA

Most bony fishes rely on suction mechanisms to capture and transport prey. Once captured, prey are carried by water movement inside the oral cavity to a second set of jaws in the throat, the pharyngeal jaws, which manipulate the prey and assist in swallowing. Moray eels display much less effective suction-feeding abilities. Given this reduction in a feeding mechanism that is widespread and highly conserved in aquatic vertebrates, it is not known how moray eels swallow large fish and cephalopods. Here we show that the moray eel (Muraena retifera) overcomes reduced suction capacity by launching raptorial pharyngeal jaws out of its throat and into its oral cavity, where the jaws grasp the struggling prey animal and transport it back to the throat and into the oesophagus. This is the first described case of a vertebrate using a second set of jaws to both restrain and transport prey, and is the only alternative to the hydraulic prey transport reported in teleost fishes. The extreme mobility of the moray pharyngeal jaws is made possible by elongation of the muscles that control the jaws, coupled with reduction of adjacent gill-arch structures. The discovery that pharyngeal jaws can reach up from behind the skull to grasp prey in the oral jaws reveals a major innovation that may have contributed to the success of moray eels as apex predators hunting within the complex matrix of coral reefs. This alternative prey transport mode is mechanically similar to the ratcheting mechanisms used in snakes—a group of terrestrial vertebrates that share striking morphological, behavioural and ecological convergence with moray eels.

Hi All-Here is an abstract from the latest issue of Nature I thought would be very interesting to those with a science bent. It describes the function of the second set of "throat" jaws in Moray eels. I can not post the whole article without violating copyright. Email the author for a full reprint. I will try to get permission to post photos. There is a link to the video at the bottom which is public. I have read the article and the figures are extremely cool and very informative. I had no idea about this anatomy in eels. It must have been the inspiration for the movie Aliens.

Nature 449, 79-82 (6 September 2007).

Raptorial jaws in the throat help moray eels swallow large prey

Rita S. Mehta1 & Peter C. Wainwright1

1. Section of Evolution and Ecology, University of California, One Shields Avenue, Davis, California 95616, USA

Most bony fishes rely on suction mechanisms to capture and transport prey. Once captured, prey are carried by water movement inside the oral cavity to a second set of jaws in the throat, the pharyngeal jaws, which manipulate the prey and assist in swallowing. Moray eels display much less effective suction-feeding abilities. Given this reduction in a feeding mechanism that is widespread and highly conserved in aquatic vertebrates, it is not known how moray eels swallow large fish and cephalopods. Here we show that the moray eel (Muraena retifera) overcomes reduced suction capacity by launching raptorial pharyngeal jaws out of its throat and into its oral cavity, where the jaws grasp the struggling prey animal and transport it back to the throat and into the oesophagus. This is the first described case of a vertebrate using a second set of jaws to both restrain and transport prey, and is the only alternative to the hydraulic prey transport reported in teleost fishes. The extreme mobility of the moray pharyngeal jaws is made possible by elongation of the muscles that control the jaws, coupled with reduction of adjacent gill-arch structures. The discovery that pharyngeal jaws can reach up from behind the skull to grasp prey in the oral jaws reveals a major innovation that may have contributed to the success of moray eels as apex predators hunting within the complex matrix of coral reefs. This alternative prey transport mode is mechanically similar to the ratcheting mechanisms used in snakes—a group of terrestrial vertebrates that share striking morphological, behavioural and ecological convergence with moray eels.

The discovery shows that morays use the second, hidden set of jaws to drag unsuspecting meals to their doom—a behavior unique among the eels' bony fish relatives, who suck in meals like vacuum cleaners.